Sensing Contact Force Related to User Wearing an Electronic Device

ABSTRACT

A wearable electronic device includes a body, a housing component, a band operable to attach the body to a body part of a user, and a force sensor coupled to the housing component. The force sensor is operable to produce a force signal based on a force exerted between the body part of the user and the housing component. A processing unit of the wearable electronic device receives the force signal from the force sensor and determines the force exerted on the housing component based thereon. The processing unit may use that force to determine a tightness of the band, determine health information for the user, adjust determined force exerted on a cover glass, and/or to perform various other actions.

CROSS-REFERENCE TO RELATED APPLICATIONS

This application is a continuation of U.S. patent application Ser. No.16/370,031, filed Mar. 29, 2019, which is a division of U.S. patentapplication Ser. No. 14/867,311, filed Sep. 28, 2015, the contents ofwhich are incorporated herein by reference as if fully disclosed herein.

FIELD

The described embodiments relate generally to wearable electronicdevices. More particularly, the present embodiments relate to sensingthe force applied to a wearable electronic device by a user's body partwhen a user is wearing the wearable electronic device.

BACKGROUND

Users frequently encounter a variety of different electronic devices inthe modern world. Such electronic devices include computers, mediaplayers, entertainment systems, displays, communication systems, and soon. Many electronic devices, such as laptop computers, tablet computers,and smart phones, may be portable.

Some electronic devices, referred to as “wearable electronic devices,”may be configured to be worn by a user. In some cases, such a wearableelectronic device may include one or more bands, straps, or otherattachment mechanisms that may be used to attach the wearable electronicdevice to a user's body part. For example, a wrist worn wearableelectronic device may include a band that can be used to secure thewearable electronic device to a user's wrist.

Wearable electronic devices may include a variety of components. Forexample, wearable electronic devices may include input devices that auser can manipulate by touch. By way of another example, wearableelectronic devices may include various sensors, such as sensors that maybe used to detect information about the user.

SUMMARY

The present disclosure relates to wearable electronic devices that sensethe force applied to the wearable electronic device by a user's bodypart when the user is wearing the wearable electronic device. Thewearable electronic device may include a body, a housing component, anda band or other attachment mechanism operable to attach the body to thebody part of a user. A force sensor may be positioned between thehousing component and the body that produces force signals based on aforce exerted between the user's body part and the housing component. Aprocessing unit may receive the force signals and process them toperform various actions.

In various embodiments, a wearable electronic device includes a body, ahousing component coupled to the body, a band operable to attach thebody to a body part of a user, a force sensor coupled to the housingcomponent that is operable to produce a force signal based on a forceexerted between the body part of the user and the housing component, anda processing unit communicably coupled to the force sensor. Theprocessing unit may be operable to determine a tightness of the bandbased on the force signal received from the force sensor.

In some examples, the force sensor may be a strain gauge mounted to adeflection element that is connected to the body and the housingcomponent. In such an example, the force signal may indicate deflectionof the deflection element based on strain data detected by the straingauge.

In various examples, the force sensor may be a gasket positioned betweenthe body of the wearable electronic device and the housing component.The gasket may include a pair of electrodes separated by a deformablematerial. In such an example, the force signal may indicate acapacitance between the pair of electrodes. The pair of electrodes mayform a capacitor and the force signal may represent a capacitance of thecapacitor.

In one or more examples, the force sensor may include an electrode. Insuch an example, the force signal may indicate a capacitance between theelectrode and the body part of the user. The electrode and the body partof the user may form a capacitor and the force signal may represent acapacitance of the capacitor. The electrode may be coupled to one of thehousing component, the body, or a circuit board coupled to the body. Insome embodiments, the electrode may be formed of indium tin oxide,nanostructures, nanomesh, nanowires, a conductive film, and so on.

In some examples, the wearable electronic device may further include acircuit board coupled to the body, and the force sensor may include afirst electrode coupled to the housing component and a second electrodecoupled to the circuit board. In such an example, the force signalreceived from the first and second electrodes may indicate a capacitancebetween the first electrode and the second electrode. In various casesof such an example, the first electrode may be a first set of electrodesand the second electrode may be a second set of electrodes. In somecases of this example the housing component may be flexible.

In some embodiments, a wearable electronic device may include a body, asurface component coupled to the body, a health sensor coupled to thebody, a force sensor coupled to the surface component, and a processingunit communicably coupled to the force sensor. The surface component maybe positioned adjacent to a body part of a user when the wearableelectronic device is worn. The health sensor may be operable to obtain ameasurement of the body part of the user. The force sensor may beoperable to produce a force signal based on a force exerted between thebody part of the user and the surface component. The processing unit maybe operable to determine health information for the user based on theforce signal received from the force sensor and the measurement obtainedby the health sensor.

In one or more examples, the health information may include at least oneof a swelling indication, a blood pressure, a body fat indication, anallergic reaction indication, a hydration indication, or an edemaindication.

In various examples, the processing unit may determine whether themeasurement obtained by the health sensor is accurate based on the forcesignal.

In some examples, the wearable electronic device may include a bandoperable to attach the body to the body part of the user. In suchexamples, the processing unit may determine a tightness of the bandbased on the force signal. If the tightness of the band is within arange of force values, the processing unit may determine the measurementobtained by the health sensor is accurate. If the tightness of the bandis outside the range of force values, the processing unit may determinethe measurement obtained by the health sensor is inaccurate.

In various examples, the wearable electronic device may further includea band operable to attach the body to the body part of the user and aband tightness adjustment mechanism. In such an example, the processingunit may determine a tightness of the band based on the force signalreceived from the force sensor and cause the tightness of the band to bealtered using the band tightness adjustment mechanism. In various cases,the processing unit may provide a notification to the user by causingthe tightness of the band to be altered.

In one or more embodiments, a wearable electronic device may include abody, a cover glass coupled to the body, a plate coupled to the body, afirst force sensor coupled to the cover glass, a second force sensorcoupled to the plate, and a processing unit communicably coupled to thefirst and second force sensors. The plate may be positioned adjacent toa body part of a user when the wearable electronic device is worn. Thefirst force sensor may be operable to produce a first force signal basedon a first force exerted on the cover glass. The second force sensor maybe operable to produce a second force signal based on a second forceexerted between the body part of the user and the plate. The processingunit may be operable to determine an amount of the first force based onthe first force signal, determine an amount of the second force based onthe second force signal, and adjust the amount of the first force basedon the second force signal.

In various examples, the processing unit may be further operable toadjust the amount of the second force based on the first force signal.For example, the first force exerted on the cover glass may causeadditional force to be exerted between the body part of the user and theplate. In order to determine the second force exerted between the bodypart of the user and the plate without the additional force beingexerted due to the first force exerted on the cover glass, the amount ofthe second force may be adjusted based on the first force signal toremove the influence of the first force.

In some examples, the processing unit may be further operable todetermine a pressure to which the body is exposed based on the firstforce signal received from the first force sensor and the second forcesignal received from the second force sensor, such as a water pressure.

In one or more examples, the processing unit may determine whether thewearable electronic device is worn by the user based on the second forcesignal received from the second force sensor.

BRIEF DESCRIPTION OF THE DRAWINGS

The disclosure will be readily understood by the following detaileddescription in conjunction with the accompanying drawings, wherein likereference numerals designate like structural elements, and in which:

FIG. 1A shows a wearable electronic device that may sense the forceexerted by a body part of a user on the wearable electronic device whenthe user is wearing the wearable electronic device.

FIG. 1B shows the wearable electronic device of FIG. 1A from the backwith the band opened.

FIG. 2A shows an example cross-sectional view of the wearable electronicdevice of FIG. 1B, taken along line A-A of FIG. 1B.

FIG. 2B shows the wearable electronic device of FIG. 2A on a user's bodypart.

FIG. 2C shows the wearable electronic device of FIG. 2B after tighteningof the band.

FIGS. 3-7 show additional examples of the wearable electronic device ofFIG. 2A in accordance with further embodiments.

FIG. 8 shows a flow chart illustrating an example method for determiningband tightness. This method may be performed by one or more of thewearable electronic devices of FIGS. 1A-7.

FIG. 9 shows a flow chart illustrating an example method for determininghealth information using a health sensor and a force sensor. This methodmay be performed by one or more of the wearable electronic devices ofFIGS. 1A-7.

FIG. 10 shows a flow chart illustrating an example method for adjustingdetected force determinations. This method may be performed by one ormore of the wearable electronic devices of FIGS. 1A-7.

FIG. 11 shows a block diagram illustrating example components that maybe utilized in the wearable electronic device and example functionalrelationships of those components.

DETAILED DESCRIPTION

Reference will now be made in detail to representative embodimentsillustrated in the accompanying drawings. It should be understood thatthe following descriptions are not intended to limit the embodiments toone preferred embodiment. To the contrary, it is intended to coveralternatives, modifications, and equivalents as can be included withinthe spirit and scope of the described embodiments as defined by theappended claims.

The description that follows includes sample systems, methods, andapparatuses that embody various elements of the present disclosure.However, it should be understood that the described disclosure may bepracticed in a variety of forms in addition to those described herein.

The following disclosure relates to wearable electronic devices operableto sense the force applied to the wearable electronic device by bodypart of a user when the user is wearing the wearable electronic device.The wearable electronic device may include a body, a housing component(such as a plate, a curved plate, or other surface component), and aband or other attachment mechanism operable to attach the body to thebody part of a user. A force sensor may be positioned between thehousing component and the body such that it produces force signals basedon a force exerted between the user's body part and the housingcomponent. A processing unit may receive the force signals and processthem to perform various actions.

For example, the processing unit may process the force signals todetermine a tightness of the band, such as for automatic bandadjustment. By way of another example, the processing unit may use theforce signals to determine health information for the user, such as incombination with measurements of the body part obtained via a healthsensor included in the body. By way of still another example, the bodymay include an input mechanism (such as a touch surface including acover glass) that interprets the force of a user's touch as input andthe processing unit may use the force signals and signals from the inputmechanism to adjust determinations of force applied to the housingcomponent or input mechanism. Various uses for the force signals fromthe force sensor are possible and contemplated.

These and other embodiments are discussed below with reference to FIGS.1A-11. However, those skilled in the art will readily appreciate thatthe detailed description given herein with respect to these Figures isfor explanatory purposes only and should not be construed as limiting.

FIG. 1A shows a wearable electronic device 100 that may sense the forceapplied to the wearable electronic device 100 when the user is wearingthe wearable electronic device 100. FIG. 1B shows the wearableelectronic device 100 of FIG. 1A from the back with the band 102 opened.

With reference to FIGS. 1A and 1B, the wearable electronic device 100may include a main body 101 that is operable to be coupled to the bodypart of a user (such as a wrist) via the band 102 or other attachmentmechanism. For example, the band 102 may be operable to attach to themain body 101 and to the body part of the user, thus attaching the mainbody 101 to the body part of the user. A housing component 104 (such asa plate, a curved plate, or other surface component) may be coupled tothe main body 101 in such a way that the wearable electronic device 100may determine the amount of force exerted by the user's body partcontacting the housing component 104 when the band 102 is attached touser. The wearable electronic device 100 may utilize the determinedforce in a variety of ways that will be discussed in detail below.

The housing component 104 may be a sensor plate associate with a sensorof the main body 101. As such, the housing component 104 may include oneor more sensor windows 105 associated with the operation of that sensor.

The band 102 may include a first band portion 103A and a second bandportion 103B. The second band portion 103B may include a band tighteningmechanism 106 that is operable to tighten the band 102 around the user'sbody part. However, it is understood that this is an example. In variousimplementations, the first band portion 103A may include such atightening mechanism instead of and/or in addition to the second bandportion 103B. Further, in some implementations, the band 102 may nothave separate portions and/or may have more than two portions withoutdeparting from the scope of the present disclosure.

FIG. 2A shows an example cross-sectional view of the wearable electronicdevice 100 of FIG. 1B, taken along line A-A of FIG. 1B. The housingcomponent 104 may be coupled to the main body 101 via a housingcomponent force sensor 210 (such as via one or more adhesives, springs,and/or other attachment mechanisms). The housing component force sensor210 may include one or more first electrodes 211 separated from one ormore second electrodes 213 by a deformable material 212 (such assilicone, an air gap, and so on). For example, the first and secondelectrodes 211 and 213 may be discrete electrodes or sets of electrodes.The first and second electrodes 211 and 213 may be included in aflexible circuit layer. The first and second electrodes 211 and 213 maybe aligned to form a capacitor. Force exerted on the housing component104 may deform the deformable material 212, changing the proximity ofthe first and second electrodes 211 and 213 and thus a capacitance of acapacitor formed by the first and second electrodes 211 and 213 (e.g.,the capacitance between the first and second electrodes 211 and 213).The housing component force sensor 210 may generate force signals thatrepresent the changes in capacitance.

A processing unit 218 may be disposed within the main body 101. In thisexample, the processing unit 218 may be disposed on a printed circuitboard 216 mounted within the body such as via one or more adhesivesand/or other attachment mechanisms. The printed circuit board 216, andthus the processing unit 218, may be connected to the housing componentforce sensor 210 via a flex circuit 214 (and/or other electrical orcommunication connection). The processing unit 218 may receive the forcesignal generated by the housing component force sensor 210 via the flexcircuit 214 and the printed circuit board 216. The processing unit 218may associate various exerted force values with various capacitancechanges. As such, the processing unit 218 may analyze the force signalto determine the force exerted on the housing component 104.

The force determined by the processing unit 218 by analyzing forcesignals may be a non-binary value. The processing unit 218 may analyzethe force signals to determine forces across a range of force values asopposed to detecting that a threshold amount of force is exerted. Theprocessing unit 218 may analyze force signals to correlate data in theforce signals to an amount of force applied out of a range of possibleforces.

The processing unit 218 may utilize the determined force exerted on thehousing component 104 for a variety of purposes. Examples that will bediscussed in further detail below include determining a tightness of theband 102 (such as for automatic band adjustment, signaling a user toadjust, and so on), determining whether or not the wearable electronicdevice 100 is being worn, and obtaining user input (such as wristmovement gestures and so on), determining health information (using thedetermined force alone and/or in combination with measurements from ahealth sensor and/or other data). Additionally or alternatively, theprocessing unit 218 may utilize the determined force exerted on thehousing component 104 in combination with force determined based onsignals from another force sensor (such as to adjust one or both of thedetermined forces, to determine pressure based on both determinedforces, and so on). However, it is understood that these are examplesand that the processing unit 218 may utilize the determined forceexerted on the housing component 104 for a variety of other purposes(such as in combination with data from one or more accelerometers,gyroscopes, altimeters, and so on) without departing from the scope ofthe present disclosure.

In some embodiments, the housing component force sensor 210 may functionas a gasket, positioned in a perimeter between the main body 101 and thehousing component 104, and forming a seal between the main body 101 andthe housing component 104. Further, although the housing component forcesensor 210 is described as a single force sensor, it is understood thatthis is an example. In various implementations, multiple housingcomponent force sensors 210 may be positioned in a perimeter between themain body 101 and the housing component 104. The multiple housingcomponent force sensors 210 may be part of a gasket or other structurethat includes the housing component force sensors 210 with thedeformable material 212 and/or other materials filling gaps in betweenthe housing component force sensors 210. In such an implementation, theprocessing unit 218 may analyze and compare force signals from eachhousing component force sensor 210 to determine one or more forcesexerted on the housing component 104 in various directions, at variouspositions, and so on.

As discussed above, the tightness of the band 102 may be determined bythe processing unit 218 using the determined force exerted on thehousing component 104. FIG. 2B shows the wearable electronic device 100of FIG. 2A on a user's body part 230 (depicted as the user's wrist,though this is merely an example and any body part may be used in otherimplementations). The user's body part 230 may exert force on thehousing component 104. The force exerted by the user's body part 230 onthe housing component 104 may be proportional to the tightness of theband 102. In other words, the tighter the band 102, the more forceexerted by the user's body part 230 on the housing component 104.Similarly, the looser the band 102, the less force exerted by the user'sbody part 230 on the housing component 104.

The tightness of the band 102 may be significant for user comfort,ensuring the wearable electronic device 100 stays attached, and so on.As such, the tightness of the band 102 may be monitored for user comfortbased on default tightness settings, user specified comfort settings,and so on. If the band 102 is too tight or too loose, the processingunit 218 may provide output instructing the user to adjust the band 102,automatically adjust the band 102 using a mechanism such as the bandtightening mechanism 106 discussed below, and/or perform other suchactions.

The tightness of the band 102 may be significant for reasons other thancomfort. In various implementations, the wearable electronic device 100may include one or more sensors and/or other components whose operationmay depend on tightness of the band 102. In such implementations, theprocessing unit 218 may provide adjustment instructions and/or adjustthe band 102 to improve operation of such sensors and/or othercomponents.

For example, a health sensor 215 may be coupled to the housing component104. In one embodiment, the health sensor 215 may be aphotoplethysmogram (PPG) sensor that emits light through the sensorwindows 105 into the user's body part 230 and receives the portion ofthe transmitted light that is reflected back from the user's body part230. The health sensor 215 may be coupled to the processing unit 218 viathe printed circuit board 216 and a flex circuit 217 (and/or otherelectrical or communication connection) and may transmit measurementsregarding the received light to the processing unit 218. The operationof the health sensor 215 may be affected by the tightness of the band102. For example, the health sensor 215 may transmit less accuratemeasurements if the band 102 is too loose. As such, the processing unit218 may provide adjustment instructions and/or tighten the band 102 toimprove operation of the health sensor 215.

FIG. 2C shows the wearable electronic device 100 of FIG. 2B aftertightening of the band 102 by the band tightening mechanism 106 ascontrolled by the processing unit 218. In this example, the second bandportion 103B may be divided into sections separated by a gap 226. Thesections may be connected to a winch mechanism 228 by cords 229 (and/orwires or other joining mechanisms). The winch mechanism 228 may becontrolled by a motor 227, which may be connected to the printed circuitboard 216, and thus the processing unit 218, via a flex circuit 225(and/or other electrical or communication connection). Thus, theprocessing unit 218 may control the winch mechanism 228 to roll and/orunroll the cords 229 to bring the sections closer and narrow the gap 226(see FIG. 2C) and/or to allow the sections to move further apart andexpand the gap 226 (See FIG. 2B).

However, it is understood that the band tightening mechanism 106 is anexample. Other band tightening mechanisms 106 constructed from variousdifferent components functioning under various different principles ofoperation can be used without departing from the scope of the presentdisclosure. For example, in some implementations, a memory wire such asNitinol may be embedded in the band 102. The processing unit 218 maycause current to be provided to such a memory wire in order to changethe shape of the memory wire, thus adjusting the tightness of the band102.

Moreover, as discussed above, the processing unit 218 may utilize thedetermined force exerted on the housing component 104 to determinewhether or not the wearable electronic device 100 is currently beingworn. In various implementations, the processing unit 218 may operate indifferent states depending on whether or not the wearable electronicdevice 100 is currently worn (such as an active state if worn and asleep or lower power state if unworn). In such implementations, theprocessing unit 218 may determine that the wearable electronic device100 is worn if the determined force exerted on the housing component 104is above a threshold force value and that the wearable electronic device100 is unworn if the determined force exerted on the housing component104 is below the threshold force value.

As also discussed above, the processing unit 218 may utilize thedetermined force exerted on the housing component 104 to obtain userinput. For example, different movements of the user's body part 230(such as bending of the wrist, flexing of the wrist, and so on) mayexert different forces on the housing component 104. The processing unit218 may analyze the determined force in order to determine how theuser's body part 230 has moved. These different movements may beinterpreted as gestures that are associated with different inputs. Assuch, the user may provide particular input to the processing unit 218by making particular movements. For example, bending of the user's bodypart 230 may indicate to the processing unit 218 that the user wants towake the wearable electronic device 100 from a sleep and/or otherwiselow power state.

As further discussed above, the processing unit 218 may utilize thedetermined force exerted on the housing component 104 to determininghealth information. In some examples, the processing unit 218 mayutilize the determined force by itself to determine health information.In other examples, the processing unit 218 may utilize the determinedforce in combination with measurements from a health sensor 215 and/ordata from other sensors or devices (such as a camera, an accelerometer,and so on).

In some implementations, the processing unit 218 may determine atightness of the band 102 based on the determined force over time. Thisdetermined tightness over time may be used to determine size changes inthe user's body part 230 over time. Using such data, the processing unit218 may be able to determine and/or detect an indication of a user'sbody fat, an indication of blood pressure, an indication of a pulserate, an indication of swelling (such as caused by an allergic reaction,perhaps to a material used in the wearable electronic device 100), anindication of an allergic reaction, an indication of hydration (such asby relaxation of swelling over time), an indication of conditions suchas edema or cutaneous edema, and so on. In various implementations, theprocessing unit 218 may utilize the determined tightness in combinationwith measurements by the health sensor 215, such as a PPG sensor, todetermine health information of the user such as blood perfusion.

In still other implementations, the processing unit 218 may receivemeasurements from the health sensor 215. However, as described earlier,the measurements transmitted by the health sensor 215 may be inaccurateor less accurate if the band 102 is too loose or too tight. As such, theprocessing unit 218 may disregard measurements from the health sensor215 if the determined force exerted on the housing component 104indicates the band 102 is too loose or too tight.

Alternatively, the processing unit 218 may attempt to obtain areplacement measurement from the health sensor 215 if the determinedforce exerted on the housing component 104 indicates the band 102 is tooloose or too tight. In such an example, measurements may be discarded ifobtained from the health sensor 215 when the determined force exerted onthe housing component 104 indicates the band 102 is too loose or tootight. In various implementations, the processing unit 218 may attemptto correct possible inaccuracies in the measurement.

As additionally discussed above, the processing unit 218 may utilize thedetermined force exerted on the housing component 104 in combinationwith force signals from another force sensor and/or data from othercomponents. In various examples, the processing unit 218 may adjust theforce determined from the other force sensor, adjust the determinedforce exerted on the housing component 104 based on the force determinedfrom the other force sensor, determine pressure based on both determinedforces, and so on.

For example, the wearable electronic device 100 may include an inputdevice that interprets exerted force as input. As shown in FIGS. 2A-2C,the main body 101 may include a cover glass 224 (which may be part of adisplay such as a touch display) coupled to the main body 101. The coverglass 224 may be coupled to a cover glass force sensor 220 (such as viaone or more adhesives or other attachment mechanisms). The cover glassforce sensor 220 may include one or more first electrodes 221 separatedfrom one or more second electrodes 223 by a deformable material 222(such as silicone, an air gap, and so on). The first and electrodes 221and 223 may form a capacitor. Force exerted on the cover glass 224 maydeform the deformable material 222, changing a capacitance of thecapacitor. The cover glass force sensor 220 may generate force signalsindicating such changes in capacitance.

The cover glass force sensor 220 may be coupled to the printed circuitboard 216, and thus the processing unit 218, via a flex circuit 219(and/or other electrical or communication connection). The processingunit 218 may receive the force signals generated by the cover glassforce sensor 220 via the flex circuit 219 and the printed circuit board216. The processing unit 218 may associate various exerted force valueswith various capacitance changes. As such, the processing unit 218 mayanalyze the force signal to determine the amount of force exerted on thecover glass 224.

The processing unit 218 may evaluate both the first force signalsgenerated by the housing component force sensor 210 corresponding to theforce exerted on the housing component 104 and the second force signalsgenerated by the cover glass force sensor 220 corresponding to the forceexerted on the cover glass 224. In some implementations, the processingunit 218 may utilize one of the force signals to adjust the other of theforce signals.

For example, a force exerted by a user on the cover glass 224 while thewearable electronic device 100 is worn may be different from a forceapplied while the wearable electronic device 100 is unworn. This may bebecause the wearable electronic device 100 is being pressed between theexertion of force on the cover glass 224 and the force between theuser's body part 230 and the wearable electronic device 100 when thewearable electronic device 100 is worn. Conversely, force exerted on thecover glass 224 is not opposed by force between the user's body part 230and the wearable electronic device 100 when the wearable electronicdevice 100 is unworn. Thus, the same amount of force exerted on thecover glass 224 could be determined to be different depending on whetheror not the wearable electronic device 100 is worn at the time.

Therefore the processing unit 218 may modify the force detected on thecover glass 224 by any force detected on the housing component 104 inorder for the processing unit 218 to determine force exerted on thecover glass 224 more uniformly regardless whether the wearableelectronic device 100 is worn or not. For example, the force detected onthe housing component 104 may be subtracted from the force detected onthe cover glass 224. By way of another example, a modifier may be addedto the force detected on the cover glass 224 when force is not detectedon the housing component 104. Such a modifier may correspond to theforce normally detected on the housing component 104 when the wearableelectronic device 100 is worn.

By way of another example, if only the force exerted on the housingcomponent 104 is used to determine the tightness of the band 102 while auser is exerting a force on the cover glass 224, the processing unit 218may determine that the band 102 is tighter than it really is. This isbecause the force exerted on the cover glass 224 also exerts force onthe housing component force sensor 210. To determine a more accuratetightness of the band 102, the processing unit 218 may subtract theforce exerted on the cover glass 224 from the force exerted on thehousing component 104 (and/or otherwise modify the determined forceexerted on the housing component 104 based on the force exerted on thecover glass 224).

In other implementations, the processing unit 218 may use both forces incombination. For example, if force is exerted on both the housingcomponent 104 and the cover glass 224 in relatively equal amounts, theprocessing unit 218 may determine that the forces are due to pressure asopposed to a user exerting force. The processing unit 218 may thenevaluate the forces to determine a pressure to which the wearableelectronic device 100 is subjected.

In some examples, the pressure may be hydrostatic pressure or waterpressure, such as where the wearable electronic device 100 is submergedin water and/or other liquid. In such an example, the processing unit218 may associate the forces detected with particular hydrostaticpressures in order to determine a depth of liquid in which the wearableelectronic device 100 is immersed.

Although a particular configuration of the housing component 104, themain body 101, and the housing component force sensor 210 are shown anddescribed, it is understood that this is an example. In otherimplementations, various configurations of the same, similar, and/ordifferent components may be utilized without departing from the scope ofthe present disclosure. For example, FIGS. 3-7 show additional examplesof the wearable electronic device 100 of FIG. 2A in accordance withfurther embodiments.

FIG. 3 illustrates an example implementation including a deflectionelement 331 coupled to one or more strain gauges 332. The deflectionelement 331 may be connected to the health sensor 315 and/or the housingcomponent 304 such that force exerted on the housing component 304 maycause the deflection element 331 to deflect. An electrical property ofthe strain gauge 332 (e.g., resistance) may change based on thedeflection. The processing unit 318 may accordingly receive forcesignals from the strain gauge 332 via a flex circuit 333 (and/or otherelectrical or communication connection) and the printed circuit board316, and may correlate the force signals to an amount of force.

The housing component 304 may be coupled to the main body 301 viaadhesive 334. The deflection element 331 may be positioned within theadhesive 334 between the housing component 304 and the main body 301. Insome examples, the adhesive 334 may be flexible such that the housingcomponent 304 is operable to move with respect to the main body 301under the exertion of force to deflect the deflection element 331. Inother examples, the adhesive 334 may form a rigid seal and the housingcomponent 304 may be flexible in order to deflect the deflection element331 under the exertion of force.

FIG. 4 illustrates an example implementation including a singleelectrode 435 formed of indium tin oxide or other material positioned onthe printed circuit board 416. The single electrode 435 may form acapacitor with the user's body part. Force exerted by the user's bodypart on the housing component 404 may change the proximity between theuser's body part and the electrode 435 thus changing the capacitance ofa capacitor formed by the user's body and the electrode 435. Theprocessing unit 418 may receive force signals from such a capacitorindicating capacitive changes and correlate the capacitive changes to anamount of force exerted on the housing component 404.

In some examples, the adhesive 434 and/or the housing component 404 maybe flexible. This may allow the user's body to move closer to theelectrode 435 under the exertion of force. The more movement that ispossible between the user's body and the electrode 435 may allow for agreater variety of capacitance differences of a capacitor formed by theuser's body and the electrode 435, allowing for greater sensitivity insensing force.

Although the electrode 435 is shown as positioned on the printed circuitboard 416, it is understood that this is an example. In variousimplementations, the electrode 435 may be positioned at differentlocations without departing from the scope of the present disclosure.For example, the electrode 435 may be positioned on the health sensor415 in some implementations. By way of another example, in variousimplementations, the electrode 435 may be positioned on the housingcomponent 404 (such as a layer of indium tin oxide, nanostructures,nanomesh, nanowires, a conductive film, and so on deposited on the innersurface of the housing component 404 facing the health sensor 415) or onthe main body 401.

FIG. 5 illustrates an example implementation including a first electrode536 positioned on the printed circuit board 516 and a second electrode537 positioned on the housing component 504 that may form a capacitor.An exertion of force on the housing component 504 may bring the firstand second electrodes 536 and 537 closer together, changing thecapacitance of a capacitor formed by the first and second electrodes 536and 537. The processing unit 518 may monitor force signals from thefirst and/or second electrodes 536 and 537 and correlate the capacitancechanges to an amount of force exerted on the housing component 504.

In some examples, the adhesive 534 and/or the housing component 504 maybe flexible. This may allow the first and second electrodes 536 and 537to move closer together under the exertion of force on the housingcomponent 504.

As compared with the example shown in FIG. 5, the example depicted inFIG. 6 includes multiple electrodes 637 (a first set of electrodes 637)positioned on the printed circuit board 616 and multiple electrodes 638(a second set of electrodes 638) positioned on the housing component604. Capacitors may be formed by pairs of electrodes of the first set ofelectrodes 637 and the second set of electrodes 638. A force applied tothe housing component 604 may bring one or more electrodes in the firstand second sets of electrodes 637 and 638 closer together, and changethe respective capacitances of those capacitors. The processing unit 618may monitor and compare force signals from one or more capacitors inorder to correlate respective capacitance changes to amounts of forceexerted at various particular locations on the housing component 604.

The adhesive 634 and/or the housing component 604 may be flexible suchthat the electrodes in the first and second sets of electrodes 637 and638 may be able to move with respect to each other independently and/orrelatively independently based on where force is exerted on the housingcomponent 604. This may enable the processing unit 618 to moregranularly determine different amounts of force exerted at differentlocations on the housing component 604.

FIG. 7 illustrates an example implementation including a flexiblehousing component 704 with a strain gauge 739 disposed thereon. Anexertion of force on the flexible housing component 704 may cause theflexible housing component 704 to flex, which may cause the strain gauge739 to deflect. An electrical property of the strain gauge 739 (e.g.,resistance) may change based on the deflection. As such, the processingunit 718 may accordingly receive force signals from the strain gauge 739indicating flexing of the flexible housing component 704 via a flexcircuit 740 (and/or other electrical or communication connection) andthe printed circuit board 716. The processing unit 718 may correlate thereceived force signals to force amounts.

FIG. 8 shows a flow chart illustrating an example method 800 fordetermining band tightness. This method 800 may be performed by one ormore of the wearable electronic devices of FIGS. 1A-7.

At 810, a force sensor may be monitored. The force sensor may bepositioned between a body of a wearable electronic device and a housingcomponent that contacts a user's body part when the wearable electronicdevice is worn.

At 820, one or more force signals may be received from the force sensorrelating to force exerted on the housing component. The force may be theforce exerted on the housing component by the user's body part and maybe related to a band of the wearable electronic device causing theuser's body part to exert the force based on a tightness of the band.

At 830, the tightness of the band associated with the force signal fromthe force sensor may be determined. Higher amounts of exerted forceindicated by the force signal may correlate to a tighter band.Conversely, lower amounts of exerted force indicated by the force signalmay correlate to a looser band.

Although the example method 800 is illustrated and described asincluding particular operations performed in a particular order, it isunderstood that this is an example. In various implementations, variousorders of the same, similar, and/or different operations may beperformed without departing from the scope of the present disclosure.

For example, in various implementations, the example method 800 mayinclude the additional operations related to band adjustment. By way ofexample, the example method 800 may include the additional operation ofdetermining whether the band tightness is within a tightness range. Thetightness range may be a range of force values. In some implementationsof such an example, the example method 800 may include the additionaloperation of causing the band to be adjusted if the band tightness isnot within the tightness range. In some cases, the user may be notifiedprior to adjustment of the band. In such cases, the user may be able tooverride band adjustment in response to such a notification.

In other implementations, the example method 800 may include theadditional operation of notifying the user that the band needsadjustment if the band tightness is not within the tightness range. Insuch implementations, the user may be prompted to adjust the band.

FIG. 9 shows a flow chart illustrating an example method 900 fordetermining health information using a health sensor and a force sensor.This method 900 may be performed by one or more of the wearableelectronic devices of FIGS. 1A-7.

At 910, a measurement may be received from a health sensor. For example,the health sensor may be a PPG sensor.

At 920, a force signal may be received from a housing component forcesensor. The housing component force sensor may be positioned between abody of a wearable electronic device and a housing component thatcontacts a user's body part. The force signal may indicate force exertedon the housing component by the user's body part.

At 930, health information for the user may be determined based on theforce signal and the measurement. For example, the force may be used todetermine the tightness of a band of the wearable device, which may beused in combination with measurements of a PPG sensor to determine ablood perfusion for the user.

Although the example method 900 is illustrated and described asincluding particular operations performed in a particular order, it isunderstood that this is an example. In various implementations, variousorders of the same, similar, and/or different operations may beperformed without departing from the scope of the present disclosure.

For example, 930 describes the health information as being determinedbased on the force signal and the measurement. However, in someimplementations, the health information may be determined based on theforce signal or the measurement without being based on both. Further,the health information may also be based on data from one or more othersensors.

By way of another example, the force may be used to determine whether ornot the health information is accurate. In some implementations, thehealth information may be accurate if the tightness of a band is withina tightness range. In such an example, the force may be used todetermine the tightness of the band is within the tightness range. Ifthe tightness of the band is not within the tightness range, the healthinformation may be discarded as inaccurate and/or may be modified basedon the force.

FIG. 10 shows a flow chart illustrating an example method 1000 foradjusting detected force determinations. This method 1000 may beperformed by one or more of the wearable electronic devices of FIGS.1A-7.

At 1010, a first force signal may be received from a cover glass forcesensor. The first force signal may indicate a force exerted on the coverglass (or other input device) by a user. The cover glass may be acomponent of a display, a touch display, and/or other assembly.

At 1020, a second force signal may be received from a housing componentforce sensor. The housing component force sensor may be positionedbetween a body of a wearable electronic device and a housing componentthat contacts a user's body part. The housing component may bepositioned on an opposite side of the wearable electronic device fromthe cover glass. The force signal may indicate force exerted on thehousing component by the user's body part.

At 1030, a force exerted on the cover glass may be determined using thefirst force signal. For example, a lookup table of first force signalvalues and force values may be consulted based on the first forcesignal. A force value corresponding to the value of the first forcesignal may be selected to determine the force exerted on the coverglass.

At 1040, a force exerted on the housing component may be determinedusing the second force signal. For example, a lookup table of secondforce signal values and force values may be consulted based on thesecond force signal. A force value corresponding to the value of thesecond force signal may be selected to determine the force exerted onthe housing component.

At 1050, the determined force on the cover glass may be adjusted usingthe second force signal. For example, the second force signal may besubtracted from the determined force on the cover glass. This may allowa determined force on the cover glass to be obtained that is free ofinfluence from forces exerted on the housing component.

Although the example method 1000 is illustrated and described asincluding particular operations performed in a particular order, it isunderstood that this is an example. In various implementations, variousorders of the same, similar, and/or different operations may beperformed without departing from the scope of the present disclosure.

For example, 1050 describes the determined force on the cover glassbeing adjusted using the second force signal. However, in variousimplementations, the determined force on the housing component may beadjusted using the first force signal instead of and/or in addition toadjusting the determined force on the cover glass using the second forcesignal.

FIG. 11 shows a block diagram illustrating example components that maybe utilized in the wearable electronic device 100 of FIG. 1A and examplefunctional relationships of those components. The wearable electronicdevice 100 may include one or more processing units 1151, force sensors1152 (such as those discussed above), storage media 1153 (such as amagnetic storage medium, an optical storage medium, a magneto-opticalstorage medium, a read only memory, a random access memory, an erasableprogrammable memory, and so on), one or more other sensors 1154 (such asone or more health sensors, accelerometers, gyroscopes, light sensors,cameras, proximity sensors, touch sensors, and so on), communicationcomponent 1155, and/or other components. The processing unit 1151 mayexecute instructions stored in the storage media 1153 in order toperform various operations discussed above.

For example, the processing unit 1151 may receive health data from ahealth sensor 1154 and may store such health data in the storage media1153. By way of another example, the processing unit 1151 may receiveforce signals from the force sensor(s) 1152 and may utilize lookuptables stored in the storage media 1153 to correlate force signals toforce amounts in order to determine amounts of applied forces, tocompare force amounts to threshold force values, to correlate forceamounts and/or threshold force values to tightnesses of a band, and soon. The processing unit 1151 may store data regarding such forcesignals, determined force amounts, determined tightnesses, and so on inthe storage media 1153. In examples where the processing unit 1151determines the tightness of a band, the processing unit 1151 may comparethe determined tightness of the band to tightness ranges stored in thestorage media 1153 to determine whether or not the determined tightnessis within such a range.

The wearable electronic device 100 may communicate with one or moreother electronic devices, such as the electronic device 1150, via thecommunication component 1155 over one or more wired and/or wirelesscommunication connections. Similar to the wearable electronic device100, the electronic device 1150 may include one or more communicationcomponents 1156, processing units 1157, storage media 1158, and/or othercomponents. In various examples, the wearable electronic device 100 maytransmit data and/or notifications regarding data to the electronicdevice 1150 via the communication components 1155 and 1156, such as theabove discussed health data, force signals, determined force amounts,determined band tightnesses, and so on. The processing unit 1157 maystore such data or notifications in the storage media 1158.

Alternatively and/or additionally, in some examples, the wearableelectronic device 100 and the electronic device 1150 may be configuredin a cooperative computing arrangement. As such, the electronic device1150 may utilize the processing unit 1157 to process the data in one ormore of the various ways the processing unit 1151 is describedprocessing such data above. For example, the processing unit 1157 mayprocess received health data to determine health information for a userof the wearable electronic device 100. By way of another example, thestorage media 1158 may store one or more lookup tables described above.As such, the processing unit 1157 may receive force signals and utilizethe lookup tables to correlate force signals to force amounts in orderto determine amounts of applied forces, to compare force amounts tothreshold force values, to correlate force amounts and/or thresholdforce values to tightnesses of a band, and so on. The processing unit1157 may store the results of such determinations in the storage media1158, transmit such results to the wearable electronic device 100,and/or perform various other operations

Although the present disclosure is described as positioning forcesensors between a housing component and a main body, it is understoodthat these are examples. In various implementations, force sensors maybe positioned anywhere on a wearable electronic device that contacts auser's body part when the wearable electronic device is worn withoutdeparting from the scope of the present disclosure. For example, a forcesensor may be positioned on an inner surface of a band that contacts auser's body part when the electronic device is worn. By way of anotherexample, a force sensor may be positioned on an outer surface of thehousing component that contacts a user's body part when the wearableelectronic device is worn. By way of still another example, a forcesensor may be positioned on a portion of the main body that contacts auser's body part when the wearable electronic device is worn.

Further, although the present disclosure is described in the context ofa wearable electronic device 100, it is understood that this is anexample. The force sensors and/or other techniques discussed herein maybe used with other devices (electronic, non-electronic, non-wearable,portable, and so on), such as the back of a smart phone, supportsattached to the bottom of a laptop computer, and/or any other devicewithout departing from the scope of the present disclosure.

As described above and illustrated in the accompanying figures, awearable electronic device may include a body, a housing component (suchas a plate, a curved plate, or other surface component), and a band orother attachment mechanism operable to attach the body to the body partof a user. A force sensor may be positioned between the housingcomponent and the body such that it produces force signals based on aforce exerted between the user's body part and the housing component. Aprocessing unit may receive the force signals and process them toperform various actions. For example, the processing unit may processthe force signals to determine a tightness of the band, such as forautomatic band adjustment. By way of another example, the processingunit may use the force signals to determine health information for theuser, such as in combination with measurements of the body part obtainedvia a health sensor included in the body. By way of still anotherexample, the body may include an input mechanism (such as a touchsurface including a cover glass) that interprets the force of a user'stouch as input and the processing unit may use the force signals andsignals from the input mechanism to adjust determinations of forceapplied to the housing component or input mechanism. Various uses forthe force signals from the force sensor are possible and contemplated.

In the present disclosure, the methods disclosed may be implemented assets of instructions or software readable by a device. Further, it isunderstood that the specific order or hierarchy of steps in the methodsdisclosed are examples of sample approaches. In other embodiments, thespecific order or hierarchy of steps in the method can be rearrangedwhile remaining within the disclosed subject matter. The accompanyingmethod claims present elements of the various steps in a sample order,and are not necessarily meant to be limited to the specific order orhierarchy presented.

The foregoing description, for purposes of explanation, used specificnomenclature to provide a thorough understanding of the describedembodiments. However, it will be apparent to one skilled in the art thatthe specific details are not required in order to practice the describedembodiments. Thus, the foregoing descriptions of the specificembodiments described herein are presented for purposes of illustrationand description. They are not targeted to be exhaustive or to limit theembodiments to the precise forms disclosed. It will be apparent to oneof ordinary skill in the art that many modifications and variations arepossible in view of the above teachings.

What is claimed is:
 1. A wearable electronic device, comprising: a body;a cover glass coupled to the body; a plate coupled to the body, theplate configured to be positioned adjacent to a portion of a user whenthe wearable electronic device is worn; a first sensor, coupled to thecover glass, that produces a first signal in response to a first forceexerted on the cover glass; a second sensor, coupled to the plate, thatproduces a second signal in response to a second force exerted betweenthe portion of the user and the plate; and a processing unit,communicably coupled to the first and second sensors, that is configuredto adjust the first signal using the second signal.
 2. The wearableelectronic device of claim 1, wherein the processing unit is configuredto adjust the second signal using the first signal.
 3. The wearableelectronic device of claim 1, wherein the processing unit determines apressure to which the body is exposed using the first signal and thesecond signal.
 4. The wearable electronic device of claim 3, wherein thepressure is a hydrostatic pressure.
 5. The wearable electronic device ofclaim 1, wherein the processing unit determines whether the wearableelectronic device is worn by the user using the second signal.
 6. Thewearable electronic device of claim 1, wherein the processing unitadjusts the first signal by subtracting the second signal from the firstsignal.
 7. The wearable electronic device of claim 1, further comprisinga band coupled to the body wherein the processing unit uses the secondsignal to determine a tightness of the band.
 8. A wearable electronicdevice, comprising: a main watch housing; a first sensor; a covercoupled to the main watch housing by the first sensor; a second sensor;a back plate coupled to the main watch housing by the second sensor; anda processing unit disposed in the main watch housing, communicablycoupled to the first sensor and the second sensor, that: determines afirst measurement using the first sensor in response to a first forceexerted on the cover; determines a second measurement using the secondsensor in response to a second force exerted on the back plate; andadjusts the first measurement using the second measurement.
 9. Thewearable electronic device of claim 8, wherein the first sensor measuresin response to the first force exerted on the cover at a same time thatthe second sensor measures in response to the second force exerted onthe back plate.
 10. The wearable electronic device of claim 8, whereinthe cover is opposite the back plate.
 11. The wearable electronic deviceof claim 8, wherein the main watch housing is positioned between thecover and the back plate.
 12. The wearable electronic device of claim 8,wherein the processing unit interprets the first measurement as a userinput.
 13. The wearable electronic device of claim 8, wherein the secondsensor comprises a capacitive sensor.
 14. The wearable electronic deviceof claim 8, wherein the second sensor comprises a strain gauge.
 15. Awearable electronic device, comprising: a cover; a plate; a main housingcoupled between the cover and the plate such that the cover is oppositethe plate; a first sensor disposed between the cover and the mainhousing; a second sensor disposed between the plate and the main housingwherein the plate is coupled to the main housing by the second sensor;and a processing unit disposed in the main housing, communicably coupledto the first sensor and the second sensor, that: determines a firstestimate in response a first force on the cover measured using the firstsensor; determines a second estimate in response to a second force onthe plate measured using the second sensor; and determines an input bysubtracting the second estimate from the first estimate.
 16. Thewearable electronic device of claim 15, wherein the processing unitdetermines a user input using a third estimate determined in response toa third force exerted on the plate.
 17. The wearable electronic deviceof claim 15, wherein the processing unit corrects the input for aninaccuracy in the first estimate by subtracting the second estimate fromthe first estimate.
 18. The wearable electronic device of claim 17,wherein the inaccuracy results from hydrostatic pressure.
 19. Thewearable electronic device of claim 17, wherein the inaccuracy resultsfrom atmospheric pressure.
 20. The wearable electronic device of claim15, wherein the first sensor is a pressure sensor.